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Intracellular signalling in blood leucocytes shows multiple aberrations in acute pancreatitis (AP) complicated by organ dysfunction (OD). We studied whether the aberrations associate with severity of AP and occur in sepsis complicated by OD. The study comprises 14 sepsis patients (11 with shock), 18 AP patients (nine mild; six moderately severe; three severe) and 28 healthy volunteers. Within 48 h after admission to hospital, phosphorylation of nuclear factor-ĸB (NF-ĸB), signal transducers and activators of transcription (STATs) 1,3, and extracellular signal-regulated kinases 1/2 were measured from stimulated or non-stimulated leucocytes using phosphospecific whole blood flow cytometry. In sepsis, as compared with healthy subjects, phosphorylated NF-ĸB levels of monocytes promoted by bacterial lipopolysaccharides, tumour necrosis factor or Escherichia coli cells were lower (P < 0.001 for all), pSTAT1 levels of monocytes promoted by IL-6 were lower (P < 0.05 for all), and STAT3 was constitutively phosphorylated in monocytes, neutrophils and lymphocytes (P < 0.001 for all). In AP, severity was associated with proportions of pSTAT1-positive monocytes and lymphocytes promoted by IL-6 (P < 0.01 for both), constitutive STAT3 phosphorylation in neutrophils (P < 0.05), but not with any of the pNF-ĸB levels. Monocyte pSTAT3 fluorescence intensity, promoted by IL-6, was lower in sepsis and AP patients with OD than in AP patients without OD (P < 0.001). Collectively, signalling aberrations in sepsis with OD mimic those described previously in AP with OD. Possibility that aberrations in STAT1 and STAT3 pathways provide novel markers predicting evolution of OD warrants studies including patients presenting without OD but developing it during follow-up.

It has been proposed that the Akt kinase pathway provides a regulatory mechanism to limit the inflammatory response. We examined the activation of Akt upon LPS challenge in monocytes of patients with rheumatoid arthritis (RA), and correlated it with disease activity. Twelve subjects with recent-onset, DMARD-naive RA, thirteen patients with chronic, DMARD therapy -nonresponding RA and 27 healthy volunteers provided whole blood samples for phosphospecific flow cytometric measurement of unstimulated and LPS-stimulated Akt phosphorylation at serine 473 in monocytes, determined in relative fluorescence units (RFU). Activation capability, i.e. responsiveness of monocytes, was determined as the difference between stimulated and unstimulated samples, and compared between groups using Mann-Whitney test. CRP and ESR, swollen and tender joint counts, patients’ global assessment of disease activity, DAS28 score, and plasma IL-6 determined by ELISA were correlated with Akt activation using Spearman method. Median (interquartile range) Akt activation capability was significantly lower in DMARD-naive (379 RFU [285, 432],], p=0.016) and even lower in DMARD-nonresponding RA (258 RFU [213, 338], p

Immaturity of the immune system renders newborns susceptible to infections. We searched for aberrations in leucocyte signalling profiles, using phospho-specific whole-blood flow cytometry, in cord blood of nine preterm (two born before 32nd gestational week) and nine full-term infants, born by caesarean section. Thirteen adults served as reference subjects. Monocyte NF-κB phosphorylation following tumour necrosis factor (TNF) or bacterial stimulation was higher in preterm neonates than in full-term neonates or adults, p38 phosphorylation following bacterial stimulation was higher in both preterm and full-term neonates than in adults, while STAT1 phosphorylation by IFN-γ or IL-6, STAT3 phosphorylation by IL-6 and STAT5 phosphorylation by GM-CSF were lower in both full-term and preterm neonates than in adults. Neutrophil STAT1 and STAT3 phosphorylation following IFN-γ stimulation and STAT5 phosphorylation following GM-CSF stimulation were lower in newborn neonates than in adults. In both CD3(+) CD4(+) and CD3(+) CD8(+) lymphocytes, NF-κB phosphorylation by TNF was higher and STAT5 phosphorylation by IL-2 was lower in preterm and full-term newborns than in adults. STAT6 phosphorylation by IL-4 was comparable in monocytes and lymphocytes of newborns and adults. The results suggest that innate immune signalling pathways responding to inflammatory stimuli are strongly functional in leucocytes of preterm neonates, which may render these neonates susceptible to inappropriate tissue injury. In leucocytes of both preterm and full-term newborns, responses needed against intracellular pathogens, and regulatory functions show immaturities, possibly contributing to worse control of infections.

The authors optimized the flow cytometric dichlorofluorescin (DCFH)-oxidation assay for buffy coat neutrophil and monocyte respiratory burst activity. Sample handlings were minimized, monocytes identified with a CD14 antibody, and viability evaluated with propidium iodide. Sodium citrate was a better anticoagulant than heparin, with a more intense Yersinia enterocolitica (YER)-induced dichlorofluorescein (DCF)-fluorescence intensity and a higher proportion of DCF-positive cells. EDTA was unsuitable as an anticoagulant with reduced cell viability and poor DCF response. Exposure of cells to YER, phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (FMLP) elicited two neutrophil subpopulations, one with low and the other with high forward light scattering properties. FMLP induced only a marginal DCF response, but after YER or PMA, virtually all neutrophils responded with an increased DCF production. During optimal conditions, the resulting DCF- fluorescence histogram was two-peaked, and the subset of cells with increased forward light scattering properties corresponded to the cells with intense DCF-fluorescence. A similar heterogeneity was frequently but not always observed amongst monocytes. The results indicate that in the peripheral blood there are at least two neutrophil and monocyte populations. One is an effective responder to stimuli, the other exhibiting a moderate response only. Properly optimized, the DCFH-oxidation assay may be used for evaluating neutrophil and monocyte subsets in a clinical setting.

Lipopolysaccharide (LPS) prepared from a rough mutant of Salmonella typhimurium and deacylated enzymatically (dLPS) does not promote neutrophil adherence to human umbilical vein endothelial cells (HUVECs). This paper reports that similarly, a smooth form of LPS prepared from Yersinia enlerocolitica O:3, a serotype known to trigger reactive arthritis in humans, and treated with alkali (yersinia LPS-OH) failed to augment neutrophil adherence to HUVECs. Studies of the mechanism underlying the poor augmentation revealed that neither enzymatically deacylated LPS from Escherichia coli J5 (J5 dLPS) nor yersinia LPS-OH stimulated expression of endothelial cell adhesion molecules E-selectin, VCAM-1 and ICAM-1, whereas both Intact J5 LPS and yersinia LPS were stimulatory. Impaired up-regulation could not be explained by decreased binding of yersinia LPS-OH to HUVECs. Furthermore, 51Cr-labelled HUVECs treated with different concentrations of yersinia LPS-OH released 51Cr in the presence of anti-yersinia anti-0 antibody and complement. J5 dLPS and yersinia LPS-OH inhibited up-regulation of the adhesion molecules induced by J5 LPS and yersinia LPS but not that induced by tumour necrosis factor alpha. Taken together, the results suggest that although yersinia LPS-OH can depress development of acute inflammation by inhibiting up-regulation of etidothelial-cell adhesion molecules, sufiicient LPS-OH is bound to induce cell injury and thereby inflammation in the prescence of specific antibody and complement. The findings may have pathogenetic implications in yersinia-triggered reactive arthritis characterized by dissemination of yersinia LPS throughout the body.

We studied functions of polymorphonuclear leucocytes (PMN) and monocytes from peripheral blood of subjects with familial hypercholesterolaemia (FH). FH monocytes exposed to Escherichia coli lipopolysaccharide (LPS) in 10% human AB serum generated tumour necrosis factor (TNF) significantly more than did control monocytes. After lowering of serum low-density lipoprotein (LDL) levels by drug treatment, FH monocytes exposed to LPS in the absence of exogenous lipoproteins generated significantly more TNF than did control monocytes. These findings suggest that increased TNF production is not affected by hypolipidaemic treatment and may not derive from differences between uptake of exogenous LDL by FH monocytes and control cells. Chemotaxis, chemokinesis, and random migration of both FH PMN and FH monocytes were normal, as determined by agarose assay and membrane filter assay. FH PMN showed increased luminol-enhanced chemiluminescence in response to 2.5 x 10(-8) M, but not to 2.5 x 10(-6) M, N-formyl-methionyl-leucyl-phenylalanine, and not to serum-treated zymosan or to phorbol myristate acetate. Luminol- and lucigenin-enhanced chemiluminescence responses of FH monocytes were normal. In summary, the major aberration found in the present study was that FH monocytes stimulated with LPS show enhanced production of TNF. The possibility that exaggerated TNF production contributes to an early development of atherosclerotic lesions in FH subjects warrants further studies.

We explored whether episodes stimulating leucocytes in vivo could be tracked from whole blood samples by monitoring activation of STAT1 by flow cytometry. The method was tested in hepatitis C patients (n = 9) that were on interferon (IFN)alpha regimen. CD14+ monocytes responded strongly to IFNalpha/gamma being sensitive indicators for recent immune activation. At 45 min after s.c. IFNalpha 91% of monocytes were phosphorylated STAT1+. The frequency of responding cells decreased to a base level within 6 h. Monocytes, however, had a long-term deficient phosphorylated STAT1 response to IFNalphain vitro that in patients on standard IFNalpha regimen lasted for 48 h. In patients on pegylated IFNalpha the phosphorylated STAT1 response was completely absent. We conclude that whole blood analysis of STAT1 activation by flow cytometry is applicable to monitor immune cells in patient material.

To apply the leukocyte migration agarose test (LMAT) to the in vitro assessment of human neutrophil chemotaxis, effects of different culture conditions on neutrophil migration under agarose were studied. Presence of either serum or human serum albumin (HSA) in the culture medium was necessary for detectable neutrophil migration. HSA was preferred since heat-stabile chemotactic agents were found to be generated from fresh serum in the presence of agarose. Additional CO2 in the assay milieu could be replaced by decreasing the NaHCO3 concentration of the culture medium. Both the directed and the spontaneous migration rates of neutrophil leukocytes increased when the concentration of agarose was decreased. Area and distance of migration and cumulative cell count of migrated neutrophil leukocytes were suitable for quantitating the neutrophil migration rate.